Forever and Ever: "Forever Plaid," the musical fantasy about an amateur four-part men's harmony group, will return to the Los Angeles area for a run at the Canon Theatre in Beverly Hills, previewing Feb. 27 and opening March 3. The production is the same one that played San Diego's Old Globe Theatre twice and was a hit at the Pasadena Playhouse last fall. . . . Also on the Westside, "The Sicilian Bachelor" has been extended at the Tiffany Theatre through March 1, with an expanded Thursday through Sunday performance schedule also announced. The cast of the farce includes Lou Cutell, Vera Lockwood and Tracy Scoggins.